My old Olympus OM lenses work quite well with a simple $15 adapter ring. Also, I have an old Tamron 17mm that works very well. Tamron used to build most of their lenses using a system they called "adaptall." Basically, the lenses were modular, so that, for example, I bought the 17mm with an Olympus mount, but if I ever wanted to use it on a Nikon, all I had to do was get the appropriated "Adaptall" mounting ring and it would work as designed. In my case, I ordered up a Canon EOS Adaptall mount from EBay, and it works exactly as if it came from the factory for the camera (manual, of course).